It is important to advertisers, content producers and broadcasters to be able to ascertain the scope and characteristics of TV viewership for their programs. However, the nature of TV viewership, where broadcast programs can be displayed to one or many viewers, and where viewers can come and go during a program, presents a challenge to the accurate measurement of such numbers and characteristics. TV viewership agencies have adopted a number of approaches to determine who is watching TV and what they are watching. For example, some agencies provide participants in TV viewership panels with a TV metering device (a piece of hardware) that can perform a number of functions related to monitoring TV viewing. For example, a TV metering device can include a microphone so that it can listen to the TV and determine which channel is being played. A TV metering device can also incorporate a user interface from which a participant can indicate when they start or stop watching the TV. In addition, a TV metering device can allow a panel participant to log into (or out of) his or her account by interacting with the device directly, through the user interface, or by sending instructions to the device using a remote control. The TV metering device then links participants' login/logout records to the corresponding TV channel information and reports them back to a remote TV viewership management server for further processing.
Setting aside the high cost of providing such a device to every household that has agreed to participate in a TV viewership survey, it may still be difficult for many participants to follow such a protocol accurately for other reasons. For example, a participant, who is watching a TV may leave the room where the TV is located to answer a call that turns out to last for an extended period of time. In this case, the TV viewership survey agency would assume that the participant is still watching the TV based on his or her login record, which constitutes a false positive data sample.